Area Forecast Discussion
Issued by NWS Jacksonville, FL
Issued by NWS Jacksonville, FL
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
151 FXUS62 KJAX 271445 AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 1045 AM EDT Thu Jun 27 2024 ...New UPDATE... .UPDATE... Issued at 1037 AM EDT Thu Jun 27 2024 Adjusted the timing and coverage of PoPs some through the afternoon, but otherwise the forecast remains on track this morning. Moist southwest flow has already initiated a few isolated storms along the Big Bend of FL this morning. With further destabilization, numerous showers and scattered storms will develop and spread ENEward across NE FL as the Gulf sea breeze tracks inland through the rest of the morning and early afternoon. During the early to mid afternoon hours (2-6 PM) the interaction between the Gulf sea breeze, pinned Atlantic sea breeze, and ongoing storm outflows will lead to strong and possibly marginally severe pulse t`storms. While showers and storms are possible anywhere today, the favored area for the stronger/severe convection will be along the I-95 corridor eastward to the beaches where a few storms could produce downburst winds around 40-60 mph. Additionally, with PWATs increasing toward two inches, rainfall rates on the order of 3-5" per hour are possible and could lead to localized flooding threats this afternoon, especially at locations that have received rain the past couple of days. Activity will generally push eastward off the coast and fade early this evening, though a week frontal zone north of the area and a weakening mid-level trough may continue showers and isolated storms into the late evening across portions of SE GA. Temperatures today will push into the mid/upper 90s once again this afternoon especially for the coastal zones. Further inland, convective activity through the early afternoon will mute heating a bit more with highs only reaching the low 90s. Peak heat index values will be between 100-106F this afternoon. For the latest NE FL and SE GA Daily Key Messages please visit: https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf && .SHORT TERM... (Friday through Saturday night) Issued at 312 AM EDT Thu Jun 27 2024 Troughing aloft will begin to de-amplify across the southeastern states on Friday as "Heat Wave" ridging expands eastward from Texas and the lower Mississippi Valley. Deep southwesterly flow will continue across our region as a stalled frontal boundary over GA lifts northward as a warm front by Friday afternoon. Convection will again be driven initially by the inland moving Gulf coast sea breeze, with scattered showers and thunderstorms likely progressing across the I-75 corridor during the mid to late morning hours, with increasing coverage during the early to mid afternoon hours across northeast FL as the Gulf coast sea breeze progresses towards the I-95 corridor, and categorical POPs were maintained for locations between I-75 and I-95. Outflow boundaries propagating northward into southeast GA will also ignite numerous afternoon and early evening thunderstorms, as southwesterly flow advects deep moisture northward in the wake of the retreating warm front, with PWATs spiking above 2 inches area-wide. Mid-level temperatures will remain mild and east-northeasterly storm motion should remain brisk on Friday, with convection likely pulsing as it encounters the pinned Atlantic sea breeze boundary along the I-95 corridor, with a few strong storms possible where mesoscale boundaries collide. Highs will generally reach the low to mid 90s area-wide, with heat index values expected to remain just below Heat Advisory criteria. Showers and thunderstorms may diminish more quickly on Friday evening as ridging aloft builds into our region and the axis of Atlantic surface ridging begins to lift northward across the FL peninsula, resulting in weakening southwesterly flow. Lows will fall to the low and mid 70s inland and the upper 70s at coastal locations. Ridging aloft expanding across the southeastern states this weekend will allow the axis of Atlantic high pressure to lift northward towards our area on Saturday. Low and mid level flow will back to a westerly direction, and a loosening local pressure gradient will allow for the Atlantic sea breeze to develop earlier on Saturday afternoon, with this boundary progressing inland and across the I-95 corridor by the mid-afternoon hours. Deep moisture, featuring PWATs above 2 inches, will persist throughout our area, resulting in numerous afternoon thunderstorms developing along the Gulf and Atlantic sea breezes, with mesoscale boundary collisions expanding coverage into inland southeast GA during the mid to late afternoon hours. Likely POPs were placed in the forecast grids area-wide on Saturday, with slower storm motion possibly resulting in locally heavy rainfall amounts, especially along the U.S. Highway 301 corridor, where the Gulf and Atlantic sea breezes will likely collide by late afternoon. Rising heights aloft will allow highs to tick upwards by a few degrees, with mid 90s inland and lower 90s at coastal locations. Heat index values may reach Heat Advisory criteria during the early to mid afternoon hours before convection and cloud cover increase during the mid to late afternoon. Mesoscale boundary collisions may keep scattered convection going through the mid-evening hours on Saturday at inland locations. Debris cloudiness will then thin out after midnight, with lows again falling to the low and mid 70s inland, ranging to the upper 70s at coastal locations. && .LONG TERM... (Sunday through Wednesday) Issued at 312 AM EDT Thu Jun 27 2024 Ridging aloft that expands into the southeastern states this weekend will briefly retrograde westward early next week as troughing progresses across the Great Lakes states and New England. Low and mid level flow will continue to weaken and will shift to north-northeasterly on Sunday, setting up a collision of the Atlantic and Gulf coast sea breezes during the late afternoon hours for locations along and west of U.S. Highway 301, where numerous to categorical POPs were placed in the forecast grids. Slow storm motion on Sunday could present a risk for locally heavy rainfall for these inland locations by late afternoon. Deep moisture will otherwise persist area-wide, fostering scattered to numerous mainly afternoon and evening thunderstorms that will develop along mesoscale boundaries. Highs on Sunday will again soar to the mid 90s inland and lower 90s at coastal locations. Convection may linger into the early evening hours on Sunday along the I-75 corridor as well as inland southeast GA. Debris cloudiness will thin out overnight, with lows generally falling to the mid 70s inland, ranging to the upper 70s at coastal locations. Troughing aloft diving southeastward towards the New England and Mid-Atlantic coasts on Monday will drive another weakening frontal boundary into the southeastern states. Low and mid level flow will veer to southwesterly as the axis of Atlantic high pressure sinks southward, resulting in convection being driven by the inland moving Gulf coast sea breeze across northeast and north central FL, while numerous afternoon and evening thunderstorms develop across southeast GA near the approaching frontal boundary. Stronger storms will be possible along the I-95 corridor as convection potentially intersects a pinned Atlantic sea breeze boundary. Highs may nudge downwards by a few degrees on Monday as convection potentially develops earlier in the afternoon. The presence of the stalling frontal boundary could keep scattered to numerous showers and thunderstorms going through the evening hours across southeast GA. Lows on Monday night will again fall to the mid and upper 70s. Long range guidance indicates that troughing aloft will nudge offshore of the Mid-Atlantic and New England coasts on Tuesday, allowing ridging to again expand back into the southeastern states by midweek. Scattered to numerous mainly afternoon and evening thunderstorms are expected again on Tuesday as the frontal boundary lingers across southeast GA and deep moisture persists across our area. Convective coverage may begin to decrease by midweek as a more subsident air mass builds overhead, especially closer to the ridge aloft across southeast GA. Scattered afternoon and evening thunderstorms will still remain possible for northeast and north central FL along inland moving sea breezes and other mesoscale boundary collisions. Highs will nudge upwards as we move towards Independence Day, with mid to upper 90s expected at inland locations beginning on Tuesday, with lower 90s for coastal locations. Heat indices may also reach Heat Advisory criteria (108 degrees) towards Tuesday and especially Wednesday. && .AVIATION...(12Z TAFS) Issued at 742 AM EDT Thu Jun 27 2024 Outside of t`storm influences, VFR conditions will prevail along with southwesterly winds around 6-12 kts with occasional gusts around 15-18 kts. Increased confidence in t`storm impacts at all sites for this afternoon, with convection possible as early as 15z at KGNV. Airfields along the I-95 corridor to the coast convective window appears to be roughly 18z-22z as activity shifts eastward into the Atlantic. Main concerns with storms this afternoon will be erratic outflow winds possible up to 30- 40kts. VFR conditions and predominant southwest flow at or below 5 kts will develop after 00z. && .MARINE... Issued at 312 AM EDT Thu Jun 27 2024 High pressure ridging over the area with fairly consistent troughing will create winds predominately from the southwest in the mornings and overnight and then shifting to south- southeasterly in the afternoons as the sea-breeze makes its way onshore. Daily afternoon showers and storms are possible over the local waters into the weekend that could linger into the evening hours. Rip Currents: Moderate rip current risk continues at NE FL and SE GA beaches today. && .PRELIMINARY POINT TEMPS/POPS... AMG 93 73 94 73 / 70 50 70 30 SSI 93 76 92 79 / 60 50 60 30 JAX 95 75 95 75 / 70 40 70 20 SGJ 94 77 93 76 / 70 30 70 30 GNV 93 75 94 74 / 70 20 70 10 OCF 91 76 94 74 / 70 20 70 20 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$